Apparatus, system, and method for multi-bitrate content streaming

ABSTRACT

An apparatus for multi-bitrate content streaming includes a receiving module configured to capture media content, a streamlet module configured to segment the media content and generate a plurality of streamlets, and an encoding module configured to generate a set of streamlets. The system includes the apparatus, wherein the set of streamlets comprises a plurality of streamlets having identical time indices and durations, and each streamlet of the set of streamlets having a unique bitrate, and wherein the encoding module comprises a master module configured to assign an encoding job to one of a plurality of host computing modules in response to an encoding job completion bid. A method includes receiving media content, segmenting the media content and generating a plurality of streamlets, and generating a set of streamlets.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/673,483, filed on Feb. 9, 2007, which is a continuation-in-part ofapplication Ser. No. 11/116,783, filed on Apr. 28, 2005, which claimsthe benefit of U.S. Provisional Application No. 60/566,831, filed onApr. 30, 2004, all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to video streaming over packet switched networkssuch as the Internet, and more particularly relates to adaptive-rateshifting of streaming content over such networks.

2. Description of the Related Art

The Internet is fast becoming a preferred method for distributing mediafiles to end users. It is currently possible to download music or videoto computers, cell phones, or practically any network capable device.Many portable media players are equipped with network connections andenabled to play music or videos. The music or video files (hereinafter“media files”) can be stored locally on the media player or computer, orstreamed or downloaded from a server.

“Streaming media” refers to technology that delivers content at a ratesufficient for presenting the media to a user in real time as the datais received. The data may be stored in memory temporarily until playedand then subsequently deleted. The user has the immediate satisfactionof viewing the requested content without waiting for the media file tocompletely download. Unfortunately, the audio/video quality that can bereceived for real time presentation is constrained by the availablebandwidth of the user's network connection. Streaming may be used todeliver content on demand (previously recorded) or from live broadcasts.

Alternatively, media files may be downloaded and stored on persistentstorage devices, such as hard drives or optical storage, for laterpresentation. Downloading complete media files can take large amounts oftime depending on the network connection. Once downloaded, however, thecontent can be viewed repeatedly anytime or anywhere. Media filesprepared for downloading usually are encoded with a higher qualityaudio/video than can be delivered in real time. Users generally dislikethis option, as they tend to want to see or hear the media fileinstantaneously.

Streaming offers the advantage of immediate access to the content butcurrently sacrifices quality compared with downloading a file of thesame content. Streaming also provides the opportunity for a user toselect different content for viewing on an ad hoc basis, whiledownloading is by definition restricted to receiving a specific contentselection in its entirety or not at all. Downloading also supportsrewind, fast forward, and direct seek operations, while streaming isunable to fully support these functions. Streaming is also vulnerable tonetwork failures or congestion.

Another technology, known as “progressive downloads,” attempts tocombine the strengths of the above two technologies. When a progressivedownload is initiated, the media file download begins, and the mediaplayer waits to begin playback until there is enough of the filedownloaded that playback can begin with the hope that the remainder ofthe file will be completely downloaded before playback “catches up.”This waiting period before playback can be substantial depending onnetwork conditions, and therefore is not a complete or fully acceptablesolution to the problem of media presentation over a network.

Generally, three basic challenges exist with regard to data transportstreaming over a network such as the Internet that has a varying amountof data loss. The first challenge is reliability. Most streamingsolutions use a TCP connection, or “virtual circuit,” for transmittingdata. A TCP connection provides a guaranteed delivery mechanism so thatdata sent from one endpoint will be delivered to the destination, evenif portions are lost and retransmitted. A break in the continuity of aTCP connection can have serious consequences when the data must bedelivered in real-time. When a network adapter detects delays or lossesin a TCP connection, the adapter “backs off” from transmission attemptsfor a moment and then slowly resumes the original transmission pace.This behavior is an attempt to alleviate the perceived congestion. Sucha slowdown is detrimental to the viewing or listening experience of theuser and therefore is not acceptable.

The second challenge to data transport is efficiency. Efficiency refersto how well the user's available bandwidth is used for delivery of thecontent stream. This measure is directly related to the reliability ofthe TCP connection. When the TCP connection is suffering reliabilityproblems, a loss of bandwidth utilization results. The measure ofefficiency sometimes varies suddenly, and can greatly impact the viewingexperience.

The third challenge is latency. Latency is the time measure form theclient's point-of-view, of the interval between when a request is issuedand the response data begins to arrive. This value is affected by thenetwork connection's reliability and efficiency, and the processing timerequired by the origin to prepare the response. A busy or overloadedserver, for example, will take more time to process a request. As wellas affecting the start time of a particular request, latency has asignificant impact on the network throughput of TCP.

From the foregoing discussion, it should be apparent that a need existsfor an apparatus, system, and method that alleviate the problems ofreliability, efficiency, and latency. Additionally, such an apparatus,system, and method would offer instantaneous viewing along with theability to fast forward, rewind, direct seek, and browse multiplestreams. Beneficially, such an apparatus, system, and method wouldutilize multiple connections between a source and destination,requesting varying bitrate streams depending upon network conditions.

SUMMARY OF THE INVENTION

The present invention has been developed in response to the presentstate of the art, and in particular, in response to the problems andneeds in the art that have not yet been fully solved by currentlyavailable content streaming systems. Accordingly, the present inventionhas been developed to provide an apparatus, system, and method foradaptive-rate content streaming that overcome many or all of theabove-discussed shortcomings in the art.

The apparatus for adaptive-rate content streaming is provided with alogic unit containing a plurality of modules configured to functionallyexecute the necessary steps. These modules in the described embodimentsinclude a receiving module configured to receive media content, astreamlet module configured to segment the media content and generate aplurality of sequential streamlets, and an encoding module configured toencode each streamlet as a separate content file.

The encoding module is further configured to generate a set ofstreamlets for each of the sequential streamlets. Each streamlet maycomprise a portion of the media content having a predetermined length oftime. The predetermined length of time may be in the range of betweenabout 0.1 and 5 seconds.

In one embodiment, a set of streamlets comprises a plurality ofstreamlets having identical time indices, and each streamlet of the setof streamlets has a unique bitrate. The receiving module is configuredto convert the media content to raw audio or raw video. The encodingmodule may include a master module configured to assign an encoding jobto one of a plurality of host computing modules in response to anencoding job completion bid. The job completion bid may be based on aplurality of computing variables selected from a group consisting ofcurrent encoding job completion percentage, average encoding jobcompletion time, processor speed, and physical memory capacity.

A system of the present invention is also presented for adaptive-ratecontent streaming. In particular, the system, in one embodiment,includes a receiving module configured to receive media content, astreamlet module configured to segment the media content and generate aplurality of sequential streamlets, each streamlet comprising a portionof the media content having a predetermined length of time, and anencoding module configured to encode each streamlet as a separatecontent file and generate a set of streamlets.

The system also includes a plurality of streamlets having identical timeindices and each streamlet of the set of streamlets having a uniquebitrate. The encoding module comprises a master module configured toassign an encoding job to one of a plurality of host computing modulesin response to an encoding job completion bid.

A method of the present invention is also presented for adaptive-ratecontent streaming. In one embodiment, the method includes receivingmedia content, segmenting the media content and generating a pluralityof sequential streamlets, and encoding each streamlet as a separatecontent file.

The method also includes segmenting the media content into a pluralityof streamlets, each streamlet comprising a portion of the media contenthaving a predetermined length of time. In one embodiment, the methodincludes generating a set of streamlets comprising a plurality ofstreamlets having identical time indices, and each streamlet of the setof streamlets having a unique bitrate.

Furthermore, the method may include converting the media content to rawaudio or raw video, and segmenting the content media into a plurality ofsequential streamlets. The method further comprises assigning anencoding job to one of a plurality of host computing modules in responseto an encoding job completion bid, and submitting an encoding jobcompletion bid based on a plurality of computing variables.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the present invention should be or are in anysingle embodiment of the invention. Rather, language referring to thefeatures and advantages is understood to mean that a specific feature,advantage, or characteristic described in connection with an embodimentis included in at least one embodiment of the present invention. Thus,discussion of the features and advantages, and similar language,throughout this specification may, but do not necessarily, refer to thesame embodiment.

Furthermore, the described features, advantages, and characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. One skilled in the relevant art will recognize that theinvention may be practiced without one or more of the specific featuresor advantages of a particular embodiment. In other instances, additionalfeatures and advantages may be recognized in certain embodiments thatmay not be present in all embodiments of the invention.

These features and advantages of the present invention will become morefully apparent from the following description and appended claims, ormay be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are nottherefore to be considered to be limiting of its scope, the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of asystem for dynamic rate shifting of streaming content in accordance withthe present invention;

FIG. 2 a is a schematic block diagram graphically illustrating oneembodiment of a media content file;

FIG. 2 b is a schematic block diagram illustrating one embodiment of aplurality of streams having varying degrees of quality and bandwidth;

FIG. 3 a is a schematic block diagram illustrating one embodiment of astream divided into a plurality of source streamlets;

FIG. 3 b is a schematic block diagram illustrating one embodiment ofsets of streamlets in accordance with the present invention;

FIG. 4 is a schematic block diagram illustrating in greater detail oneembodiment of the content module in accordance with the presentinvention;

FIG. 5 a is a schematic block diagram illustrating one embodiment of anencoder module in accordance with the present invention;

FIG. 5 b is a schematic block diagram illustrating one embodiment ofparallel encoding of streamlets in accordance with the presentinvention;

FIG. 6 a is a schematic block diagram illustrating one embodiment of avirtual timeline in accordance with the present invention;

FIG. 6 b is a schematic block diagram illustrating an alternativeembodiment of a VT in accordance with the present invention;

FIG. 6 c is a schematic block diagram illustrating one embodiment of aQMX in accordance with the present invention;

FIG. 7 is a schematic block diagram graphically illustrating oneembodiment of a client module in accordance with the present invention;

FIG. 8 is a schematic flow chart diagram illustrating one embodiment ofa method for processing content in accordance with the presentinvention;

FIG. 9 is a schematic flow chart diagram illustrating one embodiment ofa method for viewing a plurality of streamlets in accordance with thepresent invention; and

FIG. 10 is a schematic flow chart diagram illustrating one embodiment ofa method for requesting streamlets within an adaptive-rate shiftingcontent streaming environment in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Many of the functional units described in this specification have beenlabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom VLSI circuits or gate arrays,off-the-shelf semiconductors such as logic chips, transistors, or otherdiscrete components. A module may also be implemented in programmablehardware devices such as field programmable gate arrays, programmablearray logic, programmable logic devices or the like.

Modules may also be implemented in software for execution by varioustypes of processors. An identified module of executable code may, forinstance, comprise one or more physical or logical blocks of computerinstructions which may, for instance, be organized as an object,procedure, or function. Nevertheless, the executables of an identifiedmodule need not be physically located together, but may comprisedisparate instructions stored in different locations which, when joinedlogically together, comprise the module and achieve the stated purposefor the module.

Indeed, a module of executable code may be a single instruction, or manyinstructions, and may even be distributed over several different codesegments, among different programs, and across several memory devices.Similarly, operational data may be identified and illustrated hereinwithin modules, and may be embodied in any suitable form and organizedwithin any suitable type of data structure. The operational data may becollected as a single data set, or may be distributed over differentlocations including over different storage devices, and may exist, atleast partially, merely as electronic signals on a system or network.

Reference throughout this specification to “one embodiment,” “anembodiment.” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

Reference to a signal bearing medium may take any form capable ofgenerating a signal, causing a signal to be generated, or causingexecution of a program of machine-readable instructions on a digitalprocessing apparatus. A signal bearing medium may be embodied by atransmission line, a compact disk, digital-video disk, a magnetic tape,a Bernoulli drive, a magnetic disk, a punch card, flash memory,integrated circuits, or other digital processing apparatus memorydevice. In one embodiment, a computer program product including acomputer useable medium having a computer readable program of computerinstructions stored thereon that when executed on a computer causes thecomputer to carry out operations for multi-bitrate content streaming asdescribed herein.

Furthermore, the described features, structures, or characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. In the following description, numerous specific details areprovided, such as examples of programming, software modules, userselections, network transactions, database queries, database structures,hardware modules, hardware circuits, hardware chips, etc., to provide athorough understanding of embodiments of the invention. One skilled inthe relevant art will recognize, however, that the invention may bepracticed without one or more of the specific details, or with othermethods, components, materials, and so forth. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the invention.

FIG. 1 is a schematic block diagram illustrating one embodiment of asystem 100 for dynamic rate shifting of streaming content in accordancewith the present invention. In one embodiment, the system 100 comprisesa content server 102 and an end user station 104. The content server 102and the end user station 104 may be coupled by a data communicationsnetwork. The data communications network may include the Internet 106and connections 108 to the Internet 106. Alternatively, the contentserver 102 and the end user 104 may be located on a common local areanetwork, wireless area network, cellular network, virtual local areanetwork, or the like. The end user station 104 may comprise a personalcomputer (PC), an entertainment system configured to communicate over anetwork, or a portable electronic device configured to present content.For example, portable electronic devices may include, but are notlimited to, cellular phones, portable gaming systems, and portablecomputing devices.

In the depicted embodiment, the system 100 also includes a publisher110, and a web server 116. The publisher 110 may be a creator ordistributor of content. For example, if the content to be streamed werea broadcast of a television program, the publisher 110 may be atelevision or cable network channel such as NBC®, or MTV®. Content maybe transferred over the Internet 106 to the content server 102, wherethe content is received by a content module 112. The content module 112may be configured to receive, process, and store content. In oneembodiment, processed content is accessed by a client module 114configured to play the content on the end user station 104. In a furtherembodiment, the client module 114 is configured to receive differentportions of a content stream from a plurality of locationssimultaneously. For example, the client module 114 may request andreceive content from any of the plurality of web servers 116.

Content from the content server 102 may be replicated to other webservers 116 or alternatively to proxy cache servers 118. Replicating mayoccur by deliberate forwarding from the content server 102, or by a web,cache, or proxy server outside of the content server 102 asking forcontent on behalf of the client module 114. In a further embodiment,content may be forwarded directly to web 116 or proxy 118 serversthrough direct communication channels 120 without the need to traversethe Internet 106.

FIG. 2 a is a schematic block diagram graphically illustrating oneembodiment of a media content (hereinafter “content”) file 200. In oneembodiment, the content file 200 is distributed by the publisher 110.The content file 200 may comprise a television broadcast, sports event,movie, music, concert, etc. The content file 200 may also be live orarchived content. The content file 200 may comprise uncompressed videoand audio, or alternatively, video or audio. Alternatively, the contentfile 200 may be compressed using standard or proprietary encodingschemes. Examples of encoding schemes capable of use with the presentinvention include, but are not limited to, DivX®, Windows Media Video®,Quicktime Sorenson 3®, On2, OGG Vorbis, MP3, or Quicktime 6.5/MPEG-4®encoded content.

FIG. 2 b is a schematic block diagram illustrating one embodiment of aplurality of streams 202 having varying degrees of quality andbandwidth. In one embodiment, the plurality of streams 202 comprises alow quality stream 204, a medium quality stream 206, and a high qualitystream 208. Each of the streams 204, 206, 208 is a copy of the contentfile 200 encoded and compressed to varying bit rates. For example, thelow quality stream 204 may be encoded and compressed to a bit rate of100 kilobits per second (kbps), the medium quality stream 206 may beencoded and compressed to a bit rate of 200 kbps, and the high qualitystream 208 may be encoded and compressed to 600 kbps.

FIG. 3 a is a schematic block diagram illustrating one embodiment of astream 302 divided into a plurality of source streamlets 303. As usedherein, streamlet refers to any sized portion of the content file 200.Each streamlet 303 may comprise a portion of the content contained instream 302, encapsulated as an independent media object. The content ina streamlet 303 may have a unique time index in relation to thebeginning of the content contained in stream 302. In one embodiment, thecontent contained in each streamlet 303 may have a duration of twoseconds. For example, streamlet 0 may have a time index of 00:00representing the beginning of content playback, and streamlet 1 may havea time index of 00:02, and so on. Alternatively, the time duration ofthe streamlets 304 may be any duration smaller than the entire playbackduration of the content in stream 302. In a further embodiment, thestreamlets 303 may be divided according to file size instead of a timeindex and duration.

FIG. 3 b is a schematic block diagram illustrating one embodiment ofsets 306 of streamlets in accordance with the present invention. As usedherein, the term “set” refers to a group of streamlets having identicaltime indices and durations but varying bitrates. In the depictedembodiment, the set 306 a encompasses all streamlets having a time indexof 00:00. The set 306 a includes encoded streamlets 304 having low,medium, and high 204, 206, 208 bitrates. Of course each set 306 mayinclude more than the depicted three bitrates which are given by way ofexample only. One skilled in the art will recognize that any number ofstreams having different bitrates may be generated from the originalcontent 200.

As described above, the duration of one streamlet 304 may beapproximately two seconds. Likewise each set 306 may comprise aplurality of streamlets 304 where each streamlet 304 has a playableduration of two seconds. Alternatively, the duration of the streamlet304 may be predetermined or dynamically variable depending upon avariety of factors including, but not limited to, network congestion,system specifications, playback resolution and quality, etc. In thedepicted embodiment, the content 200 may be formed of the plurality ofsets 306. The number of sets 306 may depend on the length of the content200 and the length or duration of each streamlet 304.

FIG. 4 is a schematic block diagram illustrating in greater detail oneembodiment of the content module 112 in accordance with the presentinvention. The content module 112 may comprise a capture module 402, astreamlet module 404, an encoder module 406, a streamlet database 408,and the web server 116. In one embodiment, the capture module 402 isconfigured to receive the content file 200 from the publisher 110. Thecapture module 402 may be configured to “decompress” the content file200. For example, if the content file 200 arrives having been encodedwith one of the above described encoding schemes, the capture module 402may convert the content file 200 into raw audio and/or video.Alternatively, the content file 200 may be transmitted by the publisherin a format 110 that does not require decompression.

The capture module 402 may comprise a capture card configured for TVand/or video capture. One example of a capture card suitable for use inthe present invention is the DRC-2500 by Digital Rapids of Ontario,Canada. Alternatively, any capture card capable of capturing audio andvideo may be utilized with the present invention. In a furtherembodiment, the capture module 402 is configured to pass the contentfile to the streamlet module 404.

The streamlet module 404, in one embodiment, is configured to segmentthe content file 200 and generate source streamlets 303 that are notencoded. As used herein, the term “segment” refers to an operation togenerate a streamlet of the content file 200 having a duration or sizeequal to or less than the duration or size of the content file 200. Thestreamlet module 404 may be configured to segment the content file 200into streamlets 303 each having an equal duration. Alternatively, thestreamlet module 404 may be configured to segment the content file 200into streamlets 303 having equal file sizes.

The encoding module 406 is configured to receive the source streamlets303 and generate the plurality of streams 202 of varying qualities. Theoriginal content file 200 from the publisher may be digital in form andmay comprise content having a high bit rate such as, for example, 2mbps. The content may be transferred from the publisher 110 to thecontent module 112 over the Internet 106. Such transfers of data arewell known in the art and do not require further discussion herein.Alternatively, the content may comprise a captured broadcast.

In a further embodiment, the encoding module 406 is configured togenerate a plurality of sets 306 of streamlets 304. The sets 306, asdescribed above with reference to FIG. 3 b, may comprise streamletshaving an identical time index and duration, and a unique bitrate. Aswith FIG. 3 b, the sets 306 and subsequently the plurality of streams202 may comprise the low quality stream 204, the medium quality stream206, and the high quality stream 208. Alternatively, the plurality ofstreams 202 may comprise any number of streams deemed necessary toaccommodate end user bandwidth.

The encoder module 406 is further configured to encode each sourcestreamlet 303 into the plurality of streams 202 and streamlet sets 306and store the streamlets in the streamlet database 408. The encodingmodule 406 may utilize encoding schemes such as DivX®, Windows MediaVideo 9®, Quicktime 6.5 Sorenson 3®, or Quicktime 6.5/MPEG-4®.Alternatively, a custom encoding scheme may be employed.

The content module 112 may also include a metadata module 412 and ametadata database 414. In one embodiment, metadata comprises staticsearchable content information. For example, metadata includes, but isnot limited to, air date of the content, title, actresses, actors,length, and episode name. Metadata is generated by the publisher 110,and may be configured to define an end user environment. In oneembodiment, the publisher 100 may define an end user navigationalenvironment for the content including menus, thumbnails, sidebars,advertising, etc. Additionally, the publisher 110 may define functionssuch as fast forward, rewind, pause, and play that may be used with thecontent file 200. The metadata module 412 is configured to receive themetadata from the publisher 110 and store the metadata in the metadatadatabase 414. In a further embodiment, the metadata module 412 isconfigured to interface with the client module 114, allowing the clientmodule 114 to search for content based upon at least one of a pluralityof metadata criteria. Additionally, metadata may be generated by thecontent module 112 through automated process(es) or manual definition.

Once the streamlets 304 have been received and processed, the clientmodule 114 may request streamlets 304 using HTTP from the web server116. Using a standard protocol such as HTTP eliminates the need fornetwork administrators to configure firewalls to recognize and passthrough network traffic for a new, specialized protocol. Additionally,since the client module 114 initiates the request, the web server 116 isonly required to retrieve and serve the requested streamlet 304. In afurther embodiment, the client module 114 may be configured to retrievestreamlets 304 from a plurality of web servers 116.

Each web server 116 may be located in various locations across theInternet 106. The streamlets 304 may essentially be static files. Assuch, no specialized media server or server-side intelligence isrequired for a client module 114 to retrieve streamlets 304. Streamlets304 may be served by the web server 116 or cached by cache servers ofInternet Service Providers (ISPs), or any other network infrastructureoperators, and served by the cache server. Use of cache servers is wellknown to those skilled in the art, and will not be discussed furtherherein. Thus, a highly scalable solution is provided that is nothindered by massive amounts of client module 114 requests to the webserver 116 at any specific location, especially the web server 116 mostclosely associated with or within the content module 112

FIG. 5 a is a schematic block diagram illustrating one embodiment of anencoder module 406 in accordance with the present invention. In oneembodiment, the encoder module 406 may include a master module 502 and aplurality of host computing modules (hereinafter “host”) 504. The hosts504 may comprise personal computers, servers, etc. In a furtherembodiment, the hosts 504 may be dedicated hardware, for example, cardsplugged into a single computer.

The master module (hereinafter “master”) 502 is configured to receivestreamlets 303 from the streamlet module 404 and stage the streamlet 303for processing. In one embodiment, the master 502 may decompress eachsource streamlet 303 to produce a raw streamlet. As used herein, theterm “raw streamlet” refers to a streamlet 303 that is uncompressed orlightly compressed to substantially reduce size with no significant lossin quality. A lightly compressed raw streamlet can be transmitted morequickly and to more hosts. Each host 504 is coupled with the master 502and configured to receive a raw streamlet from the master 502 forencoding. The hosts 504, in one example, generate a plurality ofstreamlets 304 having identical time indices and durations, and varyingbitrates. Essentially each host 504 may be configured to generate a set306 from the raw streamlet 503 sent from the master 502. Alternatively,each host 504 may be dedicated to producing a single bitrate in order toreduce the time required for encoding.

Upon encoding completion, the host 504 returns the set 306 to the master502 so that the encoding module 406 may store the set 306 in thestreamlet database 408. The master 502 is further configured to assignencoding jobs to the hosts 504. Each host is configured to submit anencoding job completion bid (hereinafter “bid”). The master 502 assignsencoding jobs depending on the bids from the hosts 504. Each host 504generates a bid depending upon a plurality of computing variables whichmay include, but are not limited to, current encoding job completionpercentage, average job completion time, processor speed and physicalmemory capacity.

For example, a host 504 may submit a bid that indicates that based onpast performance history the host 504 would be able to complete theencoding job in 15 seconds. The master 502 is configured to select fromamong a plurality of bids the best bid and subsequently submit theencoding job to the host 504 with the best bid. As such, the describedencoding system does not require that each host 504 have identicalhardware but beneficially takes advantage of the available computingpower of the hosts 504. Alternatively, the master 502 selects the host504 based on a first come first serve basis, or some other algorithmdeemed suitable for a particular encoding job.

The time required to encode one streamlet 304 is dependent upon thecomputing power of the host 504, and the encoding requirements of thecontent file 200. Examples of encoding requirements may include, but arenot limited to, two or multi-pass encoding, and multiple streams ofdifferent bitrates. One benefit of the present invention is the abilityto perform two-pass encoding on a live content file 200. Typically, inorder to perform two-pass encoding prior art systems must wait for thecontent file to be completed before encoding.

The present invention, however, segments the content file 200 intosource streamlets 303 and the two-pass encoding to a plurality ofstreams 202 may be performed on each corresponding raw streamlet withoutwaiting for a TV show to end, for example. As such, the content module112 is capable of streaming the streamlets over the Internet shortlyafter the content module 112 begins capture of the content file 200. Thedelay between a live broadcast transmitted from the publisher 110 andthe availability of the content depends on the computing power of thehosts 504.

FIG. 5 b is a schematic block diagram illustrating one embodiment ofparallel encoding of streamlets in accordance with the presentinvention. In one example, the capture module 402 (of FIG. 4) begins tocapture the content file and the streamlet module 404 generates a firststreamlet 303 a and passes the streamlet to the encoding module 406. Theencoding module 406 may take 10 seconds, for example, to generate thefirst set 306 a of streamlets 304 a (304 a 1, 304 a 2, 304 a 3, etc.represent streamlets 304 of different bitrates). FIG. 5 b illustratesthe encoding process generically as block 502 to graphically illustratethe time duration required to process a raw or lightly encoded streamlet303 as described above with reference to the encoding module 406. Theencoding module 406 may simultaneously process more than one streamlet303, and processing of streamlets will begin upon arrival of thestreamlet from the capture module 402.

During the 10 seconds required to encode the first streamlet 303 a, thestreamlet module 404 has generated five additional 2-second streamlets303 b, 303 c, 303 d, 303 e, 303 f, for encoding and the master 502 hasprepared and staged the corresponding raw streamlets. Two seconds afterthe first set 306 a is available the next set 306 b is available, and soon. As such, the content file 200 is encoded for streaming over theInternet and appears live. The 10 second delay is given herein by way ofexample only. Multiple hosts 504 may be added to the encoding module 406in order to increase the processing capacity of the encoding module 406.The delay may be shortened to an almost unperceivable level by theaddition of high CPU powered systems, or alternatively multiple lowpowered systems.

A system as described above beneficially enables multi-pass encoding oflive events. Multi-pass encoding systems of the prior art require thatthe entire content be captured (or be complete) because in order toperform multi-pass encoding the entire content must be scanned andprocessed more than once. This is impossible with prior art systemsbecause content from a live event is not complete until the event isover. As such, with prior art systems, multi-pass encoding can only beperformed once the event is over. Streamlets, however, may be encoded asmany times as is deemed necessary. Because the streamlet is anencapsulated media object of 2 seconds (for example), multi-passencoding may begin on a live event once the first streamlet is captured.Shortly after multi-pass encoding of the first streamlet 303 a isfinished, multi-pass encoding of the second streamlet 303 b finishes,and as such multi-pass encoding is performed on a live event and appearslive to a viewer.

Any specific encoding scheme applied to a streamlet may take longer tocomplete than the time duration of the streamlet itself, for example, avery high quality encoding of a 2-second streamlet may take 5 seconds tofinish. Alternatively, the processing time required for each streamletmay be less than the time duration of a streamlet. However, because theoffset parallel encoding of successive streamlets are encoded by theencoding module at regular intervals (matching the intervals at whichthe those streamlets are submitted to the encoding module 406, forexample 2 seconds) the output timing of the encoding module 406 does notfall behind the real-time submission rate of the unencoded streamlets.Conversely, prior art encoding systems rely on the very fastestcomputing hardware and software because the systems must generate theoutput immediately in lock-step with the input. A prior art system thattakes 2.1 seconds to encode 2 seconds worth of content is considered afailure. The present invention allows for slower than real-time encodingprocesses yet still achieves a real-time encoding effect due to theparallel offset pipes.

The parallel offset pipeline approach described with reference to FIG. 5b beneficially allows for long or short encoding times without “fallingbehind” the live event. Additionally, arbitrarily complex encoding ofstreamlets to multiple profiles and optimizations only lengthens theencoding time 502 without a perceptible difference to a user because thesets 306 of streamlets 304 are encoded in a time-selective manner sothat streamlets are processed at regular time intervals and transmittedat these time intervals.

Returning now to FIG. 5 a, as depicted, the master 502 and the hosts 504may be located within a single local area network, or in other terms,the hosts 504 may be in close physical proximity to the master 502.Alternatively, the hosts 504 may receive encoding jobs from the master502 over the Internet or other communications network. For example,consider a live sports event in a remote location where it would bedifficult to setup multiple hosts. In this example, a master performs noencoding or alternatively light encoding before publishing thestreamlets online. The hosts 504 would then retrieve those streamletsand encode the streamlets into the multiple bitrate sets 306 asdescribed above.

Furthermore, hosts 504 may be dynamically added or removed from theencoding module without restarting the encoding job and/or interruptingthe publishing of streamlets. If a host 504 experiences a crash or somefailure, its encoding work is simply reassigned to another host.

The encoding module 406, in one embodiment, may also be configured toproduce streamlets that are specific to a particular playback platform.For example, for a single raw streamlet, a single host 504 may producestreamlets for different quality levels for personal computer playback,streamlets for playback on cell phones with a different, proprietarycodec, a small video-only streamlet for use when playing just athumbnail view of the stream (like in a programming guide), and a veryhigh quality streamlet for use in archiving.

FIG. 6 a is a schematic block diagram illustrating one embodiment of avirtual timeline 600 in accordance with the present invention. In oneembodiment, the virtual timeline 600 comprises at least one quantummedia extension 602. The quantum media extension (hereinafter “QMX”) 602describes an entire content file 200. Therefore, the virtual timeline(hereinafter “VT”) 600 may comprise a file that is configured to definea playlist for a user to view. For example, the VT may indicate that thepublisher desires a user to watch a first show QMX 602 a followed by QMX602 b and QMX 602 c. As such, the publisher may define a broadcastschedule in a manner similar to a television station.

FIG. 6 b is a schematic block diagram illustrating an alternativeembodiment of a VT 600 in accordance with the present invention. In thedepicted embodiment, the VT 600 may include a single QMX 602 whichindicates that the publisher desires the same content to be looped overand over again. For example, the publisher may wish to broadcast anever-ending infomercial on a website.

FIG. 6 c is a schematic block diagram illustrating one embodiment of aQMX 602 in accordance with the present invention. In one embodiment, theQMX 602 contains a multitude of information generated by the contentmodule 112 configured to describe the content file 200. Examples ofinformation include, but are not limited to, start index 604, end index606, whether the content is live 608, proprietary publisher data 610,encryption level 612, content duration 614 and bitrate values 616. Thebitrate values 616 may include frame size 618, audio channel 620information, codecs 622 used, sample rate 624, and frames parser 626.

A publisher may utilize the QVT 600 together with the QMX 602 in orderto prescribe a playback order for users, or alternatively selectivelyedit content. For example, a publisher may indicate in the QMX 602 thataudio should be muted at time index 10:42 or video should be skipped for3 seconds at time index 18:35. As such, the publisher may selectivelyskip offensive content without the processing requirements of editingthe content.

FIG. 7 is a schematic block diagram graphically illustrating oneembodiment of a client module 114 in accordance with the presentinvention. The client module 114 may comprise an agent controller module702, a streamlet cache module 704, and a network controller module 706.In one embodiment, the agent controller module 702 is configured tointerface with a viewer 708, and transmit streamlets 304 to the viewer708. Alternatively, the agent controller module 702 may be configured tosimply reassemble streamlets into a single file for transfer to anexternal device such as a portable video player.

In a further embodiment, the client module 114 may comprise a pluralityof agent controller modules 702. Each agent controller module 702 may beconfigured to interface with one viewer 708. Alternatively, the agentcontroller module 702 may be configured to interface with a plurality ofviewers 708. The viewer 708 may be a media player (not shown) operatingon a PC or handheld electronic device.

The agent controller module 702 is configured to select a quality levelof streamlets to transmit to the viewer 708. The agent controller module702 requests lower or higher quality streams based upon continuousobservation of time intervals between successive receive times of eachrequested streamlet. The method of requesting higher or lower qualitystreams will be discussed in greater detail below with reference to FIG.10.

The agent controller module 702 may be configured to receive usercommands from the viewer 708. Such commands may include play, fastforward, rewind, pause, and stop. In one embodiment, the agentcontroller module 702 requests streamlets 304 from the streamlet cachemodule 704 and arranges the received streamlets 304 in a staging module709. The staging module 709 may be configured to arrange the streamlets304 in order of ascending playback time. In the depicted embodiment, thestreamlets 304 are numbered 0, 1, 2, 3, 4, etc. However, each streamlet304 may be identified with a unique filename.

Additionally, the agent controller module 702 may be configured toanticipate streamlet 304 requests and pre-request streamlets 304. Bypre-requesting streamlets 304, the user may fast-forward, skip randomly,or rewind through the content and experience no buffering delay. In afurther embodiment, the agent controller module 702 may request thestreamlets 304 that correspond to time index intervals of 30 secondswithin the total play time of the content. Alternatively, the agentcontroller module 702 may request streamlets at any interval less thanthe length of the time index. This enables a “fast-start” capabilitywith no buffering wait when starting or fast-forwarding through contentfile 200. In a further embodiment, the agent controller module 702 maybe configured to pre-request streamlets 304 corresponding to specifiedindex points within the content or within other content in anticipationof the end user 104 selecting new content to view. In one embodiment,the streamlet cache module 704 is configured to receive streamlet 304requests from the agent controller module 702. Upon receiving a request,the streamlet cache module 704 first checks a streamlet cache 710 toverify if the streamlet 304 is present. In a further embodiment, thestreamlet cache module 704 handles streamlet 304 requests from aplurality of agent controller modules 702. Alternatively, a streamletcache module 704 may be provided for each agent controller module 702.If the requested streamlet 304 is not present in the streamlet cache410, the request is passed to the network controller module 706. Inorder to enable fast forward and rewind capabilities, the streamletcache module 704 is configured to store the plurality of streamlets 304in the streamlet cache 710 for a specified time period after thestreamlet 304 has been viewed. However, once the streamlets 304 havebeen deleted, they may be requested again from the web server 116.

The network controller module 706 may be configured to receive streamletrequests from the streamlet cache module 704 and open a connection tothe web server 116 or other remote streamlet 304 database (not shown).In one embodiment, the network controller module 706 opens a TCP/IPconnection to the web server 116 and generates a standard HTTP GETrequest for the requested streamlet 304. Upon receiving the requestedstreamlet 304, the network controller module 706 passes the streamlet304 to the streamlet cache module 704 where it is stored in thestreamlet cache 710. In a further embodiment, the network controllermodule 706 is configured to process and request a plurality ofstreamlets 304 simultaneously. The network controller module 706 mayalso be configured to request a plurality of streamlets, where eachstreamlet 304 is subsequently requested in multiple parts.

In a further embodiment, streamlet requests may comprise requestingpieces of any streamlet file. Splitting the streamlet 304 into smallerpieces or portions beneficially allows for an increased efficiencypotential, and also eliminates problems associated with multiplefull-streamlet requests sharing the bandwidth at any given moment. Thisis achieved by using parallel TCP/IP connections for pieces of thestreamlets 304. Consequently, efficiency and network loss problems areovercome, and the streamlets arrive with more useful and predictabletiming.

In one embodiment, the client module 114 is configured to use multipleTCP connections between the client module 114 and the web server 116 orweb cache. The intervention of a cache may be transparent to the clientor configured by the client as a forward cache. By requesting more thanone streamlet 304 at a time in a manner referred to as “parallelretrieval,” or more than one part of a streamlet 304 at a time,efficiency is raised significantly and latency is virtually eliminated.In a further embodiment, the client module allows a maximum of threeoutstanding streamlet 304 requests. The client module 114 may maintainadditional open TCP connections as spares to be available should anotherconnection fail. Streamlet 304 requests are rotated among all openconnections to keep the TCP flow logic for any particular connectionfrom falling into a slow-start or close mode. If the network controllermodule 706 has requested a streamlet 304 in multiple parts, with eachpart requested on mutually independent TCP/IP connections, the networkcontroller module 706 reassembles the parts to present a completestreamlet 304 for use by all other components of the client module 114.

When a TCP connection fails completely, a new request may be sent on adifferent connection for the same streamlet 304. In a furtherembodiment, if a request is not being satisfied in a timely manner, aredundant request may be sent on a different connection for the samestreamlet 304. If the first streamlet request's response arrives beforethe redundant request response, the redundant request can be aborted. Ifthe redundant request response arrives before the first requestresponse, the first request may be aborted.

Several streamlet 304 requests may be sent on a single TCP connection,and the responses are caused to flow back in matching order along thesame connection. This eliminates all but the first request latency.Because multiple responses are always being transmitted, the processinglatency of each new streamlet 304 response after the first is not afactor in performance. This technique is known in the industry as“pipelining.” Pipelining offers efficiency in request-responseprocessing by eliminating most of the effects of request latency.However, pipelining has serious vulnerabilities. Transmission delaysaffect all of the responses. If the single TCP connection fails, all ofthe outstanding requests and responses are lost. Pipelining causes aserial dependency between the requests.

Multiple TCP connections may be opened between the client module 114 andthe web server 116 to achieve the latency-reduction efficiency benefitsof pipelining while maintaining the independence of each streamlet 304request. Several streamlet 304 requests may be sent concurrently, witheach request being sent on a mutually distinct TCP connection. Thistechnique is labeled “virtual pipelining” and is an innovation of thepresent invention. Multiple responses may be in transit concurrently,assuring that communication bandwidth between the client module 114 andthe web server 116 is always being utilized. Virtual pipeliningeliminates the vulnerabilities of traditional pipelining. A delay in orcomplete failure of one response does not affect the transmission ofother responses because each response occupies an independent TCPconnection. Any transmission bandwidth not in use by one of multipleresponses (whether due to delays or TCP connection failure) may beutilized by other outstanding responses.

A single streamlet 304 request may be issued for an entire streamlet304, or multiple requests may be issued, each for a different part orportion of the streamlet. If the streamlet is requested in severalparts, the parts may be recombined by the client module 114 streamlet.

In order to maintain a proper balance between maximized bandwidthutilization and response time, the issuance of new streamlet requestsmust be timed such that the web server 116 does not transmit theresponse before the client module 114 has fully received a response toone of the previously outstanding streamlet requests. For example, ifthree streamlet 304 requests are outstanding, the client module 114should issue the next request slightly before one of the three responsesis fully received and “out of the pipe.” In other words, request timingis adjusted to keep three responses in transit. Sharing of bandwidthamong four responses diminishes the net response time of the other threeresponses. The timing adjustment may be calculated dynamically byobservation, and the request timing adjusted accordingly to maintain theproper balance of efficiency and response times.

The schematic flow chart diagrams that follow are generally set forth aslogical flow chart diagrams. As such, the depicted order and labeledsteps are indicative of one embodiment of the presented method. Othersteps and methods may be conceived that are equivalent in function,logic, or effect to one or more steps, or portions thereof, of theillustrated method. Additionally, the format and symbols employed areprovided to explain the logical steps of the method and are understoodnot to limit the scope of the method. Although various arrow types andline types may be employed in the flow chart diagrams, they areunderstood not to limit the scope of the corresponding method. Indeed,some arrows or other connectors may be used to indicate only the logicalflow of the method. For instance, an arrow may indicate a waiting ormonitoring period of unspecified duration between enumerated steps ofthe depicted method. Additionally, the order in which a particularmethod occurs may or may not strictly adhere to the order of thecorresponding steps shown.

FIG. 8 is a schematic flow chart diagram illustrating one embodiment ofa method 800 for processing content in accordance with the presentinvention. In one embodiment the method 800 starts 802, and the contentmodule 112 receives 804 content from the publisher 110. Receivingcontent 804 may comprise receiving 804 a digital copy of the contentfile 200, or digitizing a physical copy of the content file 200.Alternatively, receiving 804 content may comprise capturing a radio,television, cable, or satellite broadcast. Once received 804, thestreamlet module 404 generates 808 a plurality of source streamlets 303each having a fixed duration. Alternatively, the streamlets 303 may begenerated with a fixed file size.

In one embodiment, generating 808 streamlets comprises dividing thecontent file 200 into a plurality of two second streamlets 303.Alternatively, the streamlets may have any length less than or equal tothe length of the stream 202. The encoder module 406 then encodes 810the streamlets 303 into sets 306 of streamlets 304, in a plurality ofstreams 202 according to an encoding scheme. The quality may bepredefined, or automatically set according to end user bandwidth, or inresponse to pre-designated publisher guidelines

In a further embodiment, the encoding scheme comprises a proprietarycodec such as WMV9®. The encoder module 406 then stores 812 the encodedstreamlets 304 in the streamlet database 408. Once stored 812, the webserver 116 may then serve 814 the streamlets 304. In one embodiment,serving 814 the streamlets 304 comprises receiving streamlet requestsfrom the client module 114, retrieving the requested streamlet 304 fromthe streamlet database 408, and subsequently transmitting the streamlet304 to the client module 114. The method 800 then ends 816.

FIG. 9 is a schematic flow chart diagram illustrating one embodiment ofa method 900 for viewing a plurality of streamlets in accordance withthe present invention. The method 900 starts and an agent controllermodule 702 is provided 904 and associated with a viewer 708 and providedwith a staging module 709. The agent controller module 702 then requests906 a streamlet 304 from the streamlet cache module 704. Alternatively,the agent controller module 702 may simultaneously request 906 aplurality of streamlets 304 the streamlet cache module 704. If thestreamlet is stored 908 locally in the streamlet cache 710, thestreamlet cache module 704 retrieves 910 the streamlet 304 and sends thestreamlet to the agent controller module 702. Upon retrieving 910 orreceiving a streamlet, the agent controller module 702 makes 911 adetermination of whether or not to shift to a higher or lower qualitystream 202. This determination will be described below in greater detailwith reference to FIG. 10.

In one embodiment, the staging module 709 then arranges 912 thestreamlets 304 into the proper order, and the agent controller module702 delivers 914 the streamlets to the viewer 708. In a furtherembodiment, delivering 914 streamlets 304 to the end user comprisesplaying video and or audio streamlets on the viewer 708. If thestreamlets 304 are not stored 908 locally, the streamlet request ispassed to the network controller module 706. The network controllermodule 706 then requests 916 the streamlet 304 from the web server 116.Once the streamlet 304 is received, the network controller module 706passes the streamlet to the streamlet cache module 704. The streamletcache module 704 archives 918 the streamlet. Alternatively, thestreamlet cache module 704 then archives 918 the streamlet and passesthe streamlet to the agent controller module 702, and the method 900then continues from operation 910 as described above.

Referring now to FIG. 10, shown therein is a schematic flow chartdiagram illustrating one embodiment of a method 1000 for requestingstreamlets 304 within an adaptive-rate shifting content streamingenvironment in accordance with the present invention. The method 1000may be used in one embodiment as the operation 911 of FIG. 9. The method1000 starts and the agent controller module 702 receives 1004 astreamlet 304 as described above with reference to FIG. 9. The agentcontroller module 702 then monitors 1006 the receive time of therequested streamlet. In one embodiment, the agent controller module 702monitors the time intervals Δ between successive receive times for eachstreamlet response. Ordering of the responses in relation to the orderof their corresponding requests is not relevant.

Because network behavioral characteristics fluctuate, sometimes quitesuddenly, any given Δ may vary substantially from another. In order tocompensate for this fluctuation, the agent controller module 702calculates 1008 a performance ratio r across a window of n samples forstreamlets of playback length S. In one embodiment, the performanceratio r is calculated using the equation:

$r = {S\frac{n}{\sum\limits_{i = 1}^{n}\; \Delta_{i}}}$

Due to multiple simultaneous streamlet processing, and in order tobetter judge the central tendency of the performance ratio r, the agentcontroller module 702 may calculate a geometric mean, or alternativelyan equivalent averaging algorithm, across a window of size m, and obtaina performance factor φ:

$\phi_{current} = \left( {\prod\limits_{j = 1}^{m}\; r_{j}} \right)^{\frac{1}{m}}$

The policy determination about whether or not to upshift 1010 playbackquality begins by comparing φ_(current) with a trigger threshold Θ_(up).If φ_(current)≧Θ_(up), then an up shift to the next higher qualitystream may be considered 1016. In one embodiment, the trigger thresholdΘ_(up) is determined by a combination of factors relating to the currentread ahead margin (i.e. the amount of contiguously available streamletsthat have been sequentially arranged by the staging module 709 forpresentation at the current playback time index), and a minimum safetymargin. In one embodiment, the minimum safety margin may be 24 seconds.The smaller the read ahead margin, the larger Θ_(up) is to discourageupshifting until a larger read ahead margin may be established towithstand network disruptions. If the agent controller module 702 isable to sustain 1016 upshift quality, then the agent controller module702 will upshift 1017 the quality and subsequently request higherquality streams. The determination of whether use of the higher qualitystream is sustainable 1016 is made by comparing an estimate of thehigher quality stream's performance factor, φ_(higher), with Θ_(up). Ifφ_(higher)≧Θ_(up) then use of the higher quality stream is consideredsustainable. If the decision of whether or not the higher stream rate issustainable 1016 is “no,” the agent controller module 702 will notattempt to upshift 1017 stream quality. If the end of the stream hasbeen reached 1014, the method 1000 ends 1016.

If the decision on whether or not to attempt upshift 1010 is “no”, adecision about whether or not to downshift 1012 is made. In oneembodiment, a trigger threshold Θ_(down) is defined in a manneranalogous to Θ_(up). If φ_(current)>Θ_(down) then the stream quality maybe adequate, and the agent controller module 702 does not downshift 1018stream quality. However, if φ_(current)≦Θ_(down), the agent controllermodule 702 does downshift 1018 the stream quality. If the end of thestream has not been reached 1014, the agent controller module 702 beginsto request and receive 1004 lower quality streamlets and the method 1000starts again. Of course, the above described equations and algorithmsare illustrative only, and may be replaced by alternative streamletmonitoring solutions.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A system for adaptive-rate content streamingvideos for playback on end user stations, the system comprising a set ofone or more servers including, a storage device to store a plurality ofdifferent copies of a same single video each encoded at a different bitrate and each divided into a plurality of streamlets that collectivelystore data to playback the entire video but that individually store datato playback only a portion that starts at a unique time index and whoseduration is less than the entire playback duration of the single video,wherein the time indexes of the streamlets are the same for thedifferent copies such that the streamlets with the same time indexesfrom the different copies independently yield the same portions of thesingle video, and wherein each of the streamlets of each of thepluralities is a separate content file that is independently playable bythe end user stations, and a web server, to be executed on the set ofservers, wherein the web server is configured to: receive, for a set ofone or more initial and sequential ones of the time indexes, at leastone streamlet request over a set of one or more network connections froma requesting one of the end user stations to retrieve the separatecontent files storing the portions of the single video starting at theset of time indexes from one of the different copies; retrieve from thestorage device the requested content files from the one copy; send theretrieved content files from the one copy to the requesting one of theend user stations over the set of network connections; receive, for eachsubsequent time index, at least one streamlet request over the set ofnetwork connections from the requesting one of the end user stations toretrieve the separate content files storing the portion of the singlevideo starting at that time index from one of the different copiescurrently selected, wherein the requesting one of the end user stationsselects the currently selected one of the different copies dependentupon ongoing determinations to shift the playback quality to a higher orlower quality one of the different copies, wherein the shifts inplayback quality occur at the time indexes; retrieve from the storagedevice the requested content files from the currently selected one ofthe different copies; and send the retrieved content files from thecurrently selected one of the different copies to the requesting one ofthe end user stations over the set of network connections.
 2. The systemof claim 1, wherein the set of servers does not require a specializedprotocol for said adaptive-rate content streaming.
 3. The system ofclaim 1, wherein at least one of the set of one or more servers is acache server.
 4. The system of claim 1, wherein the web server receivesthe streamlet requests using a standard protocol.
 5. The system of claim1, wherein the web server receives the streamlet request as HypertextTransport Protocol (HTTP) GET requests.
 6. The system of claim 1,wherein at least one of the set of one or more servers is a contentserver, and wherein the content server includes a content moduleincluding, the web server; a receiving module configured to receive thevideos; a streamlet module configured to segment the received videos togenerate for each a plurality of sequential raw streamlets thatcollectively store data to playback the entire video and thatindividually store data to playback only a portion that starts at aunique time index and whose duration is less than the entire duration ofthe corresponding video; and an encoding module configured to encodeeach raw streamlet to generate, for each of said raw streamlets, a setincluding an encoded streamlet for each bitrate supported by theadaptive-rate content streaming, wherein each of the encoded streamletsin each of the sets is stored as the separate content file, wherein theencoded streamlets within each of the sets have the same time index astheir corresponding raw streamlet such that the encoded streamlets ofthe same set independently yield on playback the same portion of thecorresponding video, and wherein the separate content files within eachof the sets are independently requestable by end user stations.
 7. Thesystem of claim 6, further comprising a streamlet database, wherein theencoding module is further configured to transmit the separate contentfiles each storing one of the encoded streamlets to the streamletdatabase to be stored, and wherein the web server is coupled to thestreamlet database to retrieve the requested ones of the separatecontent files from the streamlet database to transmit to the requestingone of the end user stations.
 8. The system of claim 6, wherein thecontent module further comprises: a metadata module configured toreceive metadata from a publisher, wherein the metadata comprisessearchable content information; and a metadata database to store themetadata.
 9. The system of claim 8, wherein the metadata furthercomprises metadata associated with an end user navigational environmentfor the single video.
 10. The system of claim 6, wherein the encodingmodule is configured to encode multiple of the plurality of sequentialraw streamlets in parallel.
 11. The system of claim 6, wherein theencoding module is configured to encode the plurality of sequential rawstreamlets at regular intervals using an offset parallel processingscheme.
 12. The system of claim 6, wherein the encoding module comprisesa master module configured to assign an encoding job to one of aplurality of hosts to generate at least one of the separate contentfiles from at least one of the plurality of sequential raw streamlets inresponse to an encoding job completion bid received from the one host.13. The system of claim 6, wherein the encoding module is furtherconfigured to multi-pass encode each of the plurality of sequential rawstreamlets of at least one of the videos.
 14. The system of claim 13,wherein the at least one of the videos is of a live event.
 15. A methodfor adaptive-rate content streaming videos for playback on a contentplayer on an end user station, the method comprising: receiving aselected one of the videos for generating streamlets for adaptive-ratecontent streaming; and creating a plurality of different copies of thesame selected video, wherein each of the different copies is encoded ata different bit rate and is divided into a plurality of streamlets thatcollectively store data to playback the entire video but thatindividually store data to playback only a portion that starts at aunique time index and whose duration is less than the entire duration ofthe selected video, wherein the time indexes of the streamlets are thesame for the different copies such that streamlets with the same timeindexes form the different copies independently yield the same portionsof the selected video, and wherein each of the streamlets of each of thepluralities is a separate content file that is independently playable bythe end user station.
 16. The method of claim 15, wherein said creatingcomprises: encoding the selected video into each of the plurality ofdifferent copies at each of the different bit rates supported by theadaptive-rate content streaming; and segmenting each of the plurality ofdifferent copies into the plurality of streamlets, wherein each of theplurality of streamlets of each of the plurality of different copies isstored as the separate content file, and wherein the separate contentfiles within each of the sets are independently requestable by end userstations.
 17. The method of claim 15, wherein said creating comprises:segmenting the selected video and generating a plurality of sequentialraw streamlets that collectively store data to playback the entire videoand that individually store data to playback only the portion thatstarts at the unique time index and whose duration is less than theentire duration of the corresponding video; and encoding each rawstreamlet to generate, for each of said raw streamlets, a set includingan encoded streamlet for each bitrate supported by the adaptive-ratecontent streaming, wherein each of the encoded streamlets in each of thesets is stored as the separate content file, and wherein the encodedstreamlets within each of the sets have the same time index as theircorresponding raw streamlet such that the encoded streamlets of the sameset independently yield on playback the same portion of thecorresponding video, wherein the separate content files within each ofthe sets are independently requestable by end user stations.
 18. Themethod of claim 17, wherein said encoding comprises encoding multiple ofthe plurality of sequential raw streamlets in parallel.
 19. The methodof claim 17, wherein said encoding further comprises multi-pass encodingeach of the plurality of sequential raw streamlets of the correspondingvideo.
 20. A method for streaming from a set of one or more serversvideos for playback on a content player on an end user station, themethod comprising: streaming from the set of servers a selected one ofthe videos for playback on the content player, wherein the set ofservers stores a plurality of different copies of the same selectedvideo each encoded at a different bit rate and each divided into aplurality of streamlets that collectively store data to playback theentire video but that individually store data to playback only a portionthat starts at a unique time index and whose duration is less than theentire playback duration of the selected video, wherein the time indexesof the streamlets are the same for the different copies such that thestreamlets with the same time indexes from the different copiesindependently yield the same portions of the selected video, and whereineach of the streamlets of each of the pluralities is a separate contentfile that is independently playable by the end user stations, andwherein said streaming comprises: receiving, for a set of one or moreinitial and sequential ones of the time indexes, at least one streamletrequest over a set of one or more network connections from a requestingone of the end user stations to retrieve the separate content filesstoring the portions of the single video starting at the set of timeindexes from one of the different copies; retrieving from the storagedevice the requested content files with the set of time indexes from theone copy; sending the retrieved content files from the one copy to therequesting one of the end user stations over the set of networkconnections; receiving, for each subsequent time index, at least onestreamlet request over the set of network connections from therequesting one of the end user stations to retrieve the separate contentfiles storing the portion of the single video starting at that timeindex from one of the different copies currently selected, wherein therequesting one of the end user stations selects the currently selectedone of the different copies dependent upon successive determinations toshift the playback quality to a higher or lower quality one of thedifferent copies, wherein the shifts in playback quality occur at thetime indexes; retrieving from the storage device the requested contentfiles with the time index from the currently selected one of thedifferent copies; and sending the retrieved content files from thecurrently selected one of the different copies to the requesting one ofthe end user stations over the set of network connections.